Chapter 21, Problem 71PP

Interpretation Introduction

Interpretation:

The condensation product for the given transformation should be predicted.

Concept introduction:

Aldol condensation reaction is where the aldol addition product undergoes dehydration to give a conjugated enone.  In organic chemistry, condensation reaction means loss of small molecules to form product.  For aldol condensation reaction to take place the starting material should have two $\alpha$ hydrogens in the same carbon atom.  The driving force for aldol condensation reaction is the formation of conjugated system.  The steps involved in aldol condensation reaction are,

• Deprotonation of $\alpha$ carbon
• Attach of enolate ion with the aldehyde (nucleophilic attack)
• Protonation of the alkoxide ion to give aldol product
• Dehydration of the aldol addition product to form conjugated enone (aldol condensation product)

Please note that aldol condensation product is formed at higher temperature.

If the condensation reaction takes place within the same molecule means a cyclic ring is formed and this is known as intramolecular aldol condensation.